Young Silver Dragon

Large dragon, lawful good

Armor Class 18 (natural armor)
Hit Points 168 (16d10 + 80)
Speed 40 ft., fly 80 ft.

Saving Throws Dex +4, Con +9, Wis +4, Cha +8
Skills Arcana +6, History +6, Perception +8, Stealth +4
Damage Immunities cold
Senses blindsight 30 ft., darkvision 120 ft., passive Perception 18
Languages Common, Draconic
Challenge 9 (5,000 XP)

Actions

Multiattack. The dragon makes three attacks: one with its bite and two with its claws.
Bite. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 17 (2d10 + 6) piercing damage.
Claw. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 13 (2d6 + 6) slashing damage.
Breath Weapons (Recharge 5–6). The dragon uses one of the following breath weapons.
Cold Breath. The dragon exhales an icy blast in a 30-foot cone. Each creature in that area must make a DC 17 Constitution saving throw, taking 54 (12d8) cold damage on a failed save, or half as much damage on a successful one.
Paralyzing Breath. The dragon exhales paralyzing gas in a 30-foot cone. Each creature in that area must succeed on a DC 17 Constitution saving throw or be paralyzed for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.